1. Field of the Invention
The present invention relates to robotic devices and methods for instrument targeting. In particular, the invention relates to systems and methods for computer assisted image-based instrument targeting, under portable x-ray fluoroscopy based image servoing.
2. Description of the Related Art
Minimally invasive and noninvasive procedures for surgery are gaining increased popularity mainly due to reduced trauma to patients and improved recovery time. One of the main problems encountered in minimally invasive procedures is, in contrast to open surgical procedures, a dramatic reduction in the surgeon's visual ability. Accordingly, radiological, ultrasonic, and magnetic resonance imaging techniques are employed to map anatomical geometry during intra-operative procedures.
Systems and methods for image guided instrument targeting are known. Manual and computer assisted instrument targeting is known. Some existing methods for computer assisted instrument targeting under fluoroscopy use complex robot-image registration algorithms. However, these same approaches use static images of fiducial markers to estimate robot-image coordinate mapping, which is then used for targeting.
Manual fluoroscopy-guided interventions are normally based on trial and error requiring considerable surgical skill and operative training. Automatic targeting has the potential to reduce the required level of surgical experience and the variability among surgeons in performing this type of procedures.
Portable ultrasonic and fluoroscopy units (commonly termed C-Arms) are ubiquitous in modern operating rooms. Both of these affordable imagers provide real time two-dimensional (2-D) visualization. A common impediment in using these 2-D imagers is the lack of volumetric representation necessitating extensive surgical training for correct 3-D interpretation. The problem of “retrofitting” computer image-based 3-D navigation systems on commonplace C-arms is complicated by the fact that the vast majority of portable fluoroscopy systems do not provide encoding of the C-Arm position or orientation. This creates difficulty in estimating the pose of the imager with respect to the patient, thus complicating computer assisted procedures using this image information. Many solutions have been proposed for helping surgeons in performing fluoroscopy guidance. See Desbat L., Champleboux g., Fleute M., Komarek P., Mennessier C., Monteil B., Rodet T., Bessou P., Coulomb M., Ferretti G., “3D Interventional Imaging with 2D X-Ray Detectors”, Medical Image Computing and Computer-Assisted Intervention, September 1999, Cambridge, England: Lecture Notes in Computer Science, Springer-Verlag, Vol. 1679, pp 973–980, 1999; Gueziec A., Kazanzides P., Williams B., Taylor R. H., “Anatomy-Based Registration of CT-Scan and lntraoperative X-Ray Images for Guiding a Surgical Robot”, IEEE Transactions on medical Imaging, 17(5):715–728, 1998; the contents of which are incorporated herein by reference.
For example, an efficient algorithm allowing for the complete reconstruction of volumetric anatomy using multiple 2-D images is proposed in Navab, N., Bani-Hashemi, A., Nadar, M. S., Wiesent, K., Durlak, P., Brunner, T., Barth, K., Graumann, R.: “3D Reconstruction from Projection Matrices in a C-Arm Based 3D-Angiography system”, 1998 MICCAI, Lecture Notes in Computer Science, Springer-Verlag, Vol. 1679, pp 688–705, 1999; the contents of which are incorporated herein by reference.
Simultaneously, other researchers concentrated on the development of image guidance and registration techniques for various fluoroscopy guided interventions. See Desbat et al., supra; Gueziec et al., supra; Potamiakos, P., Davies, B. L. Hilbert R. D. “Intra-operative imaging guidance for keyhole surgery methodology and calibration”, Proc. First Int. Symposium on Medical Robotics and Computer Assisted Surgery, Pittsburgh, Pa. P. 98–104; Stoianovivi, D., Cadedu, J. A., Demaree, R. D., Basile H. A., Taylor, R. Whitcomb, L. L., Sharpe, W. N. Jr., Kavoussi, L. R.: “An efficient Needle Injection Technique and Radiological Guidance Method for Percutaneous Procedures”, 1997 CVRMed-MrCas, Lecture Notes in Computer Science, Springer-Verlag, Vol. 1205, pp. 295–298, 1997; the contents of which are incorporated herein by reference.
Most image guided instrument targeting procedures, such as percutaneous needle access, and radio and ultrasonic ablation, require targeting of a specific instrument/probe at an exact organ location. The clinical outcome of these procedures significantly relies on targeting accuracy.
To address this problem, computer-assisted instrument targeting systems have been developed based on specialized image registration algorithms. Such methods commonly use at least two images of a spatial radio-opaque marker of complex geometry or a series of one-dimensional marks distributed on a defined pattern. See Bzostek, A., Schreiner, S., Barnes, A. C., Cadeddu, L. A. Roberts, W., Anderson, J. H., Taylor, R. H., Kavoussi, L. R.: “An automated system for precise percutaneous access of the renal collecting system”, Lecture Notes in Computer Science, Springer-Verlag, Vol. 1205, pp. 299–308, 1997; the contents of which are incorporated herein by reference.
The x-ray projection of the markers is used to estimate the instrument-image coordinate mapping, which is then used for targeting. These algorithms compute the exact position of the target with respect to the instrument and the geometrical parameters of the imager, such as the source position, magnification factor, etc. In these procedures, distortion correction and image calibration techniques are usually required for increased accuracy. These approaches are considered to be “fully calibrated” systems and methods. See Bzosteket al., supra; Jao J., Taylor, R. H., Goldberg, R. P., Kumar, R, Bzostek, A., Van Vorhis, R., Kazanzides, P., Guezniec, A., Funda, J., “A progressive Cut Refinement Scheme for Revision Total Hip Replacement Surgery Using C-arm Fluoroscopy”, lecture Notes in Computer Science, MICCAI 1999, pp. 1010–1019; the contents of which are incorporated herein by reference.
Thus, there is a need for new and improved image based target guiding systems and methods that take advantage of commonly available imaging technology and solve problems with the prior art.